chondrite

(stony meteorites showing no melting)

A chondrite is a stony meteorite that does not show
signs of overall melting. They typically include round grains
(chondrules) which are interpreted as rapidly melted
and cooled aggregates of cosmic dust and as
material formed very early in the life of the solar system.
There is not a consensus on the details of their formation,
i.e., what could cause the required heating and cooling.
Theories: